.
Damage inflicted
The earthquake caused damage in an
area of about 20,000 square kilometers, from
northwest of Manila through Central Luzon
and into the mountains of the Cordillera
Administrative Region. About 1,600 people
were killed, mostly in the central Luzon and lack of heavy equipment to cut through the
Cordillera region. This was one of the steel reinforcement of fallen concrete.
deadliest and costliest natural disasters in the Agencies reported how some of the victims
Philippines. died not from collapsing infrastructure but from
dehydration.
Baguio City
Pangasinan
Baguio City, a popular tourist
destination, was one of the hardest hit areas In Dagupan City, about 90 buildings in the city
with the number of deaths estimated at around were damaged, and about 20 collapsed. Some
1,000. Several private and public buildings structures sustained damage because
were severely damaged or destroyed, many of liquefaction caused buildings to sink as much
which were hotels. One of the buildings as 1 meter (39 inches). The earthquake
destroyed was a five-star Hyatt Hotel; one 12- caused a decrease in the elevation of the city
story section collapsed over the lobby area and several areas were flooded. 47 were
killing about 50 people. The five-star Nevada injured and 17 died. Most injuries were
Hotel was also damaged beyond repair when sustained during stampedes at a university
the lower level collapsed, killing about 40 building and a theater.
people. Many affected residents who lost their
homes ended up setting up tents in public Five municipalities in La Union were affected:
parks such as in Burnham Park, or in the Agoo, Aringay, Caba, Santo Tomas, and
streets. Kennon Road, one of the major routes Tubao with a combined population of 132,208.
from Manila to Baguio City, was shut down Many buildings collapsed or were severely
due to severe landslides. damaged. 2,387 families were displaced when
two coastal villages sank. The province
For the first 48 hours after the suffered 493 casualties including 32 deaths.
earthquake, the city was isolated from the rest
of the country. Electric, water, and References
communication lines were destroyed. The city
^ The July 16 Luzon Earthquake, Philippine
was inaccessible by land because of
Institute of Volcanology and Seismology 2001
landslides and inaccessible by air, except to
helicopters, because of damage at the airport. ^ International notes Earthquake Disaster -
Food and fuel were scarce. Because hospital Luzon, Philippines
buildings were damaged, patients were
relocated under tents set up in open spaces in
front of the hospitals. Damage to homes and
the occurrence of many aftershocks caused
most residents to set up camps in open
spaces in the city. Three days after the
earthquake, a main road leading to the city
was cleared to enable delivery of supplies.
International notes Earthquake Disaster -
Luzon, Philippines
More than 1,000 people are killed
Nueva Ecija when a 7.7-magnitude earthquake strikes
Luzon Island in the Philippines on this day in
Cabanatuan City has many concrete buildings, 1990. The massive tremor wreaked havoc
but most of them are only three stories high. across a sizeable portion of Luzon, the
The only building that collapsed during the countrys largest island, with Baguio City
earthquake was Philippine Christian College, suffering the most devastating effects. The
the tallest building in the city with six floors, epicenter of the quake, which struck at 4:26
trapping 274 students inside. All in all there p.m., was north of Manila in the Nueva Ecija
were about 363 casualties, including 154 province. Reports indicate that the shaking
deaths. Rescue efforts were hampered by the
went on for nearly a full minute. Collapsing tens of kilometers away from the ground
buildings were the main cause of damage and rupture or earthquake epicenter. These were
death. Getting out of a multi-story building was Baguio, Agoo and Dagupan City. To determine
a good safety precaution that afternoon, aftershock pattern and to understand why
although many people were injured and a few heavy damages were incurred by these areas,
even died in stampedes of others doing the PHIVOLCS closely monitored the ensuing
same thing. At Christian College, a six-story aftershock activity by operating temporary
building completely collapsed, trapping seismic stations in strategically located sites
approximately 250 students and teachers around the aftershock area, in addition to its
inside. Heroic rescue efforts saved many, but existing seismic stations. Aftershocks lie along
some victims who did not die in the collapse the ground rupture zone and around the
were found dead later from dehydration Baguio and Agoo areas. The aftershocks
because they were not pulled out in time. All pattern and the distribution of heavy damages
types of buildings, including several resort and impacts to environment suggest the
hotels in Baguio, known as the Philippines possibility that two sequences of faulting might
Summer Capital, suffered tremendous have occurred: along a main fault, the
damage. Most of the citys 100,000 residents Philippine Fault-Digdig Fault system located at
slept outdoors that evening and during the Nueva Ecija and Nueva Vizcaya provinces and
following week, afraid to return to their homes an E-W oriented subfault close to Baguio clip
amid the frequent aftershocks. For days, and Agoo. Aside from factors like topographic
workers pulled bodies from the demolished effect, differential site response and seismic
buildings in Baguio. The best estimate is that wave radiation pattern, the movement of the
1,000 bodies were eventually recovered. At said subfault could have contributed to the
least another 1,000 people suffered serious extensive damage in Baguio City. Focal
injuries. Rescue efforts were hampered mechanism data of strong aftershocks as
severely because the three main roads into published by the National Earthquake
the city were blocked by landslides. Hundreds Information Center (NEIC) were plotted on
of motorists were stranded on the roads as map and section to evaluate the possible
well. Outside of Baguio, a chemical factory fire sense of movement and orientation of stress
also caused terrible damage. The Tuba gold fields. The dominant mechanism of strong
and copper mine in the area lost 30 workers aftershocks occurring in the Baguio area
when a mine collapsed. Baguio, sitting on at indicates an extensional type of faulting which
least seven fault lines, is now listed as one of is in agreement with the sense of left-lateral
the most risk-prone cities in Asia. In addition to movement of the main fault.
the risk of earthquakes, the areas high annual
rainfall increases the likelihood of deadly The earthquake was triggered by the
landslides. American military personnel sudden movement of the northwest segment
stationed in the Philippine archipelago took of Philippine Fault Zone (PFZ) and of its north
part in the relief effort. The area was revisited trending splay, Digdig Fault. The PFZ is an
by disaster less than a year later when Mount active fault system which can be traced from
Pinatubo erupted. Some geologists believe the Mindanao in south eastern Philippines, going
two events were connected. north west and passing through the islands of
Leyte, Masbate, Ticao Island, Bondoc
Ref: Peninsula, Dingalan to Lingayen, Pangasinan
(Figure 1). Based on geologic data, the age of
http://www.history.com/this-day-in- the 1200-km long fault is estimated as
history/earthquake-wreaks-havoc-in-the- Pliocene (Barrieret et.al., 1991). The latest
philippines pre-1990 movement of this fault occurred on,
17 March 1973 at Ragay Gulf in Quezon
Province. That earthquake, with Ms of 7.5,
The 16 July 1990 Luzon earthquake resulted to horizontal displacements of 1.1 to
severely affected areas which were several 3.4 meters. Along the rupture with no evident
vertical component (Morante, 1974). From
1500 to 1983 at least 25 strong earthquakes along the Pacific Oceans Ring of Fire and
(Figure 2) could be correlated to the having 5 major fault lines, it is vulnerable to
movement of PFZ (Punongbayan and Umbal, disasters such as earthquakes. The country is
1990). The most obvious geomorphological no stranger to earthquakes, but one of the
evidence of its recent movements could be most memorable to hit it is the quake that hit
found in Leyte in a series of offset streams and the island of Luzon in 1990. That powerful
fault scarps. Other geomorphic features have quake resulted in a number of collapsed
been observed from field observations, buildings and thousands of lives lost. At
satellite imagery, aerial photographs and around 4 pm on July 16, 1990, a magnitude-
seismic profiles (Barrier, et.al., 1991). 7.8 earthquake hit Northern and Central
According to Barrier et.al. (1991), there are Luzon. Its epicenter was recorded in Nueva
two main segments the Philippine Fault - Ecija, and the shaking lasted for about a
central section from Bondoc peninsula to minute. Among the hardest hit areas were the
Mindanao and the northern segment. The cities of Baguio, Cabanatuan in Nueva Ecija,
central segment is purely left-lateral strike-slip and Dagupan in Pangasinan. In Baguio City,
based on kinematic indicators while the several structures collapsed, burying people
northern segment has a thrust component. alive. Some establishments destroyed
included hotels like the Hyatt Terraces Plaza,
Nevada Hotel, Baguio Hilltop Hotel, Baguio
Park Hotel, and FRB Hotel. Because of shocks
At around 4 pm on July 16, 1990, a
and fear of possible aftershocks, thousands of
magnitude-7.8 earthquake hit Northern and
residents slept on the streets. The quake left
Central Luzon. Its epicenter was recorded in
an estimated US$369-million worth of
Nueva Ecija, and the shaking lasted for about
damages, and a total of 2,412 people dead.
a minute.Among the hardest hit areas were
Lessons The 1990 earthquake left not just
the cities of Baguio, Cabanatuan in Nueva
massive damage and casualties, but also
Ecija, and Dagupan in Pangasinan.In Baguio
lessons about disaster readiness. Philippine
City, several structures collapsed, burying
Institute for Volcanology and Seismology
people alive. Some establishments destroyed
(PHIVOLCS) Director Renato Solidum said the
included hotels like the Hyatt Terraces Plaza,
great earthquake left us with 4 valuable
Nevada Hotel, Baguio Hilltop Hotel, Baguio
lessons. 1. Public needs to respond properly
Park Hotel, and FRB Hotel.Because of shocks
during earthquakes According to Solidum, not
and fear of possible aftershocks, thousands of
much attention was given to disasters,
residents slept on the streets.The quake left
especially earthquakes, at the time. In fact,
an estimated US$369-million worth of
earthquake drills were unheard of then.
damages, and a total of 2,412 people
Fortunately, earthquake drills are often
dead.The 1990 earthquake left not just
conducted lately. This is in anticipation of a
massive damage and casualties, but also
7.2-magnitude earthquake that could be
lessons about disaster readiness.
produced by the movement of the West Valley
Fault, and of a tsunami that could result from
https://www.rappler.com/newsbreak/iq/63417-
the movement of the Manila Trench. (READ:
remembering-1990-luzon-earthquake
#MMShakeDrill: Metro-Wide Earthquake Drill
2017) 2. Hazards and their effects should be
simulated After the earthquake, transportation
The 1990 Luzon earthquake left some and communication lines were all affected,
valuable lessons. Have we learned them yet? leaving Baguio isolated from the outside. The
Gwen de la Cruz Published 4:27 PM, July 16, government did not have any idea about what
2014 Updated 10:12 AM, July 14, 2017 'WAR the situation in Baguio was like then. Taking
ZONE'. The aftermath of the 1990 Luzon off from that, Solidum said it is important for
earthquake. Photo from PHIVOLCS MANILA, people to be aware of the hazards in their
Philippines The Philippines is the third most areas so that if a disaster happens, they are
disaster-prone countryin the world. Located not left clueless about developments should
communication lines be cut or roads blocked.
3. Building codes should be implemented
properly, and land use should be carefully
planned. Despite having sevral collapsed and
destroyed buildings, a good number of them
were left standing then. Solidum said the
country's building code is actually good, but
the problem lies in implementation. Good
design, quality materials, and good
workmanship are needed for a disaster-
resilient building. When it comes to land use
planning, he said that buildings should not be
constructed in areas prone to landslides.
Shaking does not kill people. Collapsing
buildings will, Solidum said. 4. Trained search
and rescue groups and medical responders
are needed. Immediate response after an
earthquake could be a problem, especially if
there is a lack of rescue groups and
responders. According to Solidum, the golden
rule is: "People must be rescued within the first
3 days." But are we ready? In 2004, a study
funded by the Japan International Cooperation
Agency, theMetro Manila Earthquake Impact
Reduction Study (MMEIRS) found that a 7.2
magnitude earthquake could hit Metro Manila
and could destroy 40% of the establishments
in the metropolis and kill around 34,000
https://www.rappler.com/newsbreak/iq/63417-
remembering-1990-luzon-earthquake
